United States Patent Publication 20070173960 (Kumar), which is incorporated by reference herein in its entirety, allegedly discloses a “compact lower cost programmable logic controller with modular I/O is described. SPI bus is used for accessing multi-byte data from I/O modules, while 8 bit data bus is used to access single byte data from I/O modules. Compact I/O modules with use with the PLC are described. The include short circuit proof DC output modules, Relay output with built-in electromagnetic shield, analog modules with laser trimmed resistors, and high speed counter modules.” See Abstract.
U.S. Pat. No. 6,536,029 (Boggs), which is incorporated by reference herein in its entirety, allegedly discloses a “programmable logic controller with enhanced and extended the capabilities. A digital input filter implement filters with considerable less logic by simulating the action of a capacitor being driven by a constant current source whose output voltage is sensed by a comparator with a large amount of hysterisis. A pulse catch circuit captures the input pulse even though the update occurs between scan cycles. A pulse output controller includes a hardware pipeline mechanism to allow for smooth, hardware-controlled transitions from wave-form to wave-form. A free port link allows the user to control the port either manually or by operation of a user program. In order to provide higher performance for communication using PPI protocol, the PLC includes a built-in protocol. A n-bit modem protocol ensures data integrity without use of a parity type data integrity system. A hide instruction protects proprietary software by encrypting the sensitive code and decrypting the code during compilation and, thereafter, re-encrypting the code. A system function call allows the user to create and/or download new PLC functions and implement them as PLC operating system functions. An STL status function debugs programs during run-time and while the program is executing. A micro PLC arrangement provides compact size and efficiency.” See Abstract.